In order to remove the dirt and other constituents deposited on the upper rollers of a drafting system during operation, stripping apparatuses whose stripping edges are in contact with the circumferential surface of the rollers at a certain contact pressure are used in practice. For example, flexible strippers, which are in contact with the circumference of the rollers at a certain angle of attack and at a certain prestress, are used. The flexible strippers are usually fastened to a holder, by means of which they are fastened to the drafting system.
Such an apparatus is known, for example, from EP 1 700 937 B1. To remove the material stripped by the strippers of the stripping device from the area of the upper rollers, a suction hood is provided above the stripping apparatus, the hood being connected to a vacuum source.
In order to prevent accumulation of the components stripped off on the respective stripper, the strippers are periodically lifted up from the circumferential surface of the rollers to be stripped periodically at certain intervals by means of a suitably mounted adjusting device or shifted horizontally with respect to the axle of the roller.
Such apparatuses are known in general as indicated, for example, in EP 1 700 937 B1 and also DE 38 29 490 A1.
The tendency to constantly increase machine productivity also results in higher rotational speeds of the upper rollers and lower rollers on the drafting systems. This in turn results in the fact that the amount of material strip brought by the stripper apparatuses per unit of time is increased. This may result in the apparatuses known in the past no longer being capable of removing the stripped off material (dirt, fibers mixed with honeydew and other components) continuously from the area of the stripper. This can result in accumulations in this area and can ultimately cause interfere with the drawing operation. On the one hand, this has a negative impact on the stripping function of the respective stripper, while on the other hand such accumulations, when they become loosened by the stripper, can enter the clamping gap between the upper roller and the lower roller and thus have a negative effect on the drawing operation. This can result in the formation of an irregular fiber sliver, which is formed downstream from the drafting system.